Testing or measuring apparatus



June 8 1926.

B. M. W. HANSON TESTING yOR MEASURING APPARATUS Filed May 2l. 1925 3Sheets-Sheet 2 June 8 i926.

B. MA. W. HANSGN 'TESTING 0R MEASURING APPARATUS 'Filed May 2l.

1925 3 Sheets-Sheet 5 Patented `lune Si, 1926.

UNITED STATES PATENT()FFIC'E.

BENGT ivi. w. HANsoimpF HARTFORD,

coivNEoTicUT; Enma A. HANsoNAND CLAR- ENCE E. WHITNEY EXECUTORS F SAIDBENGT IVI. W. HANSON, DECEASED.

TESTING OR IVIEASURING- APPARATUS.

Application filed May 21,

This invention relates to devices for testing or measuring thedimensions, spacing or trueness, etc., of various kinds of members orparts. As instances of uses to which my apparatus may be applied,reference may be had to the measurement of the distance between, orindicating the inaccuracies in the spacing of, certain elements, forinstance, spaced apart grooves or ribs; or to the measurement of variousdimensions of pieces of work. My improved apparatus is particularlyapplicable for use in testing, for instance, the lead of a screw threadby determining the distance to which the successive convolutions of thethread are spaced apart. Vlt is, of course, evident that I hereindisclose for illustrative purposes only several of the embodiments whichthe present invention may take, it being evident that the device issusceptible of various uses and of various modifications and changeswhich may come within the purview of the annexed claims.

rlhe aim of the invention is to provide an apparatus of this sort bymeans of Vwhich measurements may be very quickly and readily determinedwith great accuracy.

Another object of the invention is to provide an apparatus of arelatively simple nature which may be readily adjusted and quicklymanipulated to determine with eX- treme precision the extent ofinaccuracies in pieces of work, as, for instance, in the relation ofspaced apart serrations or the successive `convolutions of a threadedmember.

Other objects will be in part obvious and in part pointed outhereinafter.

The invention accordingly consists in the features of construction,combination of elements and arrangement of parts which will beexemplified in the construction illustrated in the accompanyingdrawings, wherein is disclosed one embodiment which the presentinvention may take.

in these drawings:

Figure l is a 'View in front elevation of my improved apparatus, thecover plate for the indicating Adevice being removed;

Fig. 2 is a partial view in front elevation and on an enlarged scale ofthe mechanism embodied in the indicating( device g F 3 is a sectionalview in side elevation of the indicating device, this view being takensubstantially on line 3 3 of Fig. 2;

Fig. 4 is a side elevational View looking ltowards the right end of Fig.l;

1923. Serial No. 640,348.

lmeans for clamping the fulcrum member 7" in adjusted position on thebase a.

Referring to the drawings in detail, and particularly tov Figs. l to 5inclusive, a indicates 'a ease of any suitable construction providedwith longitudinal ways b on which are mounted for sliding or adjustablemovement means for supporting the piece to be tested as,'for instance,the headand tail stocks c and (l, respectively. Also, provided on thebase in parallelism, with thelongitudinal ways are Vthe ways c slidablysuportinoP a rest of fulcrum member on the P e top of which isfulcrumed, as by means of knife edges g, aswinging support or arm Lcarrying on its forward end a longitudinally extending head or bracketz' provided with longitudinally extending ways 7c. Mounted foradjustment on these ways is an indicator slide Z on the front face ofwhich is secured a casing m which supports and houses the indicatormechanism.l This indicator mechanism includes a point n adapted forengagement with the piece to be tested, an indicating finger o, and aconnection between the point and finger through which a slight movementof thepoint causes a relatively large movement of the finger,ashereinafter described morein detail. rlhe letter p indicates generally adrop pin arrangement by means of which, in combination with suitableAgauge blocks adapted to` be selectively interposed between thisarrangement p and the indicator, the latter may be very accuratelyadjusted to operating position. Rough adjustment of the indicatingdevice may be effected by turning the knob (l directly mounted on thescrew rassociated with the indicator slide Z, and fine adjustment iseffected by turning the knob `s, which is connected up with the screw r,through the intermeshing pinion t and gear u,

When the piece to be tested -is in the form of a gauge plug or screw,this piece is mounted between the centers 10 and 11 of the head and tailstocks, the center 10 being longitudinally adjusted upon turning thehand wheel 12. The center 11 is slidably mounted in the tail stock cl,being normally urged to engage the work by a spring 15 interposedbetween the rear end of the center and a bushing 13 xed in the outer endof the tail stock d. 14 designates a screw having a bearing in thebushing 13 and adapted to move axially in the bushing. In the rear endof the center 11 is fixed a nut 100 which has threaded engagement withthe screw. The spring 15 surrounds that portion of the screw between thebushing and the rear end of the center. To adjust the center, it ismerely necessary to rotate the screw 14 which has a handle 101 on itsouter end. The spring 15 normally urges the center 11 towards `theopposed center 10. The supporting means for the work will, of course,vary, depending on characteristics of the work. For example, the blockc', of Figs. 8 and 9, may be used where it is desired to measure thedimensions of a cylinder.

The rest or fulcrum member f has, at its opposite ends, suitable blocksor rest-s 16 provided with Vs in which the knife edges g engage, theseknife edges being carried by the lateral extensions 18 of the swingingsupport h. For the purpose of preventing lateral movement of theswinging arm, the knives g are positioned between suitable thrust pins19 mounted in brackets 20 arising from the opposite ends of the memberf. Preferably, the knife edges g are pointed at the corners at whichthey engage the pins 19, so as to reduce friction to a minimum. Thepointed corners of the knife edges are designated by the numeral 115.The rest or fulcrum member j may be clamped in any position ofadjustment by means of a binding bolt 21. The means for clamping therest f in any position of adjustment may be of any suitable sort. Forillustrative purposes, only, I have shown, in Fig. 4, the clamping bolt21 as having an eccentric stud 105 on its inner end engaging 1n anopening 106 in a pin 107 having a head 108 located in a T-slot 109 inthe base. Then the clamp is turned in the proper direction, the stud 105thereof lifts on the pin 107 so as to bind the head 108 'against theupper wall of the slot 109. The forward end of the swinging arm isnormally returned to and held in raised position by a tension spring 22.The spring pressed plunger 23 limits, without shock, the extent ofmovement of the swinging arm, and the latter may be eounterbalanced byan adjustable weight 24.

The indicator slide screw r is journalled 1n a bracket 25 carried by theright hand end of the head z'. Also journalled in this bracket forlongitudinal sliding movement is a shaft 26 to which is secured, or onwhich is milled, the small pinion t and the operating knob or handle s.llt is to be noted that to adjust the indicating device in accordancewith the length or character of the piece to be tested, the fulcrummember y, together with the parts carried thereby, will be moved to, andthen clamped position. During the testing operation, when it is desiredto quickly move the mdieating device, the screw r will be turneddirectly by the knob g thereon, and when it is desired to slowly andvery accurately move the indicating device, the knob s will be turned soas to rotate the screw through the pinion t and gear u, the latter beingfixed to the screw. Mounted on the screw i" is a Idial or scale 27 whichcooperates with an indicating mark 28 so that the position, or theextent of movement, of the indicating device may be quickly determinedwith approximate accuracy. Then the knob q is turned, the pinion is outof mesh with the gear u, the pinion having been moved to the positionshown in Fig. 1. lhen the knob s is to be turned, it is drawn out so tobring the pinion and gear into mesh.

rThe indicator will now be described in detail. Pivoted to the frontface and adjacent the lower end of the bracket fm, is a point lever 31having, at its lower end, a socket 32 adapted to receive the point n,the operative end of which is in the form of a small sphere, as shown.The point lever 31 is pivoted, as stated, by means of a knife edge 33,engaging in the V of the block or rest secured to the bracket m.Adjacent the upper end of the point lever 31 is a depending knife edge35 which engages in a V 36 carried by a link lever 37 supported by aspring 38. Adjacent the opposite end of the link lever 37 is a V 40 inwhich engages a depending knife edge 41 carried by, what may be termedfor convenience, a magnifying lever 42 to the lower end of which issecured the weight 43. The purpose of the weight is to counterbalancethe lever so as to normally urge the same into vertical position. To theforward face of this weight is attached by welding or otherwise, therelatively light-weight linger 0. The magnifying lever 42 is in the formof an inverted U straddling the right hand end of the lever 37. Thismagnifying lever is provided at the end of each leg with alined knifeedges 44 engaging in the inverted Vs 45 located in the lower end of ablock 46 secured to the bracket on by screws 47. It will be seen thatthe vertical distance between the knife edge 41 on the one hand, and theknife edges 44 on the other is relatively short. The spring 38 isconnected at its upper end to a pin 48 projecting from the in, properCFI block L16, and at its lower end to the intermedia-te portionv ot'the link lever 37.

1t will be seen that the spring 38 supports and maintains in positionthe point lever, the link lever 37 and the magnifying leverI a2,together' with the parts carried thereby. ln other words, the severalcooperating knife edges and V seats oi the indicating device aren'iaintained in cooperative relation by the spring 33. The indicatordevice may be housed, or not, as desired within a suitable casing suchas that indicated by the numeral 50. At the upper end of this casing isa scale 5l with which the free end of the linger 0 cooperates. When thepoint is brought into engagement with the piece to be tested and therebymoved, say t'or instance, to the right, referring to Figs. 1*.2, theupper end of the point lever moves substantially three times thisdistance toward the leit't drawing the link lever 37 with it, andthereby causing the finger o to swing about its tulcrum constituted bythe knife edges 1-5.

lt will be understood that al very slight, in 'fact extremely minute,movement of the point n will, through the system of links and leversdescribed, be so transmitted to the .linger 0 that the tree end of thelatter will have a relatively large movement, swinging through an arcover the scale 51 many times greater than the extent oi movement of thepointer. In the embodiment disclosed, this movement is substantially inthe ratio of one hundred and titty to one. The feature of pivotallysupporting and connecting the movable parts of the indicator by means ofknife edges is ot the utmost advantage, for with. this arrangement theparts may be positioned with the greatest accuracy, frietion issubstantially eliminated, andi there is practically no wear; all ofwhich means that the indicator will have a long life during which theparts remain constant in their relation to one another, thus maintainingthe maximum eliciency and practically eliminating the introduction ofall errors on account of wear or the like. `1

Secured to the side ot the casing is a plate or anvil 53 which is placedopposite an operating stud or plunger 54 o the drop pin arrangement p.This plunger 5ftis mounted for sliding movement in a bracket 55 securedto the left hand end of the head or slide bracket z'. Fixed to theplunger is Aa collar 56 between which and a bushing 57 fixed to thebracket is interposed a. spring 58 which urges the plungertowards theright, referring to Figs. l and 5. The collar and plunger are maintainedagainst rotation by a key 59 secured to the collar and having slidingmovement in a key-way 60 provided in the bracket 55. This key may beextended through the collar so as to form a projection 6l for limitingthe dropping movement ot the drop pin. Secured to the collar is a stud62, and carried by the bracket is an alined stud 63 and between thesestuds the drop 64 is adaptedA to be positioned. .This drop pin has ahead with its side iaces in paralle ism with each other, and a Vstem asis `most clearly shown in Fig. 5.

`For the purpose of successively positioning the indicator at spaceddistances as, for exam ple, in accordance with the desired lead oi thescrewithread tested, a plurality ot' gauge blocks are provided. One ofsaid blocks is shown in Fig. 5 and is designated by the numeral 66.These blocks are adapted to be selectively positioned on the surface orseat 67 between the anvil 53 and the cooperating plunger 541-.

The operation of the apparatus illustrated in Figs. l to 6, briefly, isas follows: It necessary, the ulcrum member or rest f, together with thesupport /t and the parts carried thereby, is adjusted so that the pointa o1 the indicator may be brought into engagement with the piece to betested. The drop pin (Seis positioned between the studs 62 and 63, the

position that its stem 1s suspended in a horizontal plane.

l The indicator is ynow moved with a relatively quick motion by turningthe knob Q so as to bring the anvil 53 into approximate engagement withthe plunger 54 of the drop pin ar'angement. Owing to the scale 27, theindicating device may be brought very accurately into such position thatthe anvil is` almost in engagementwith the plunger 54, and thus a savingof time will be eiected in adjusting the device, since, thereafter, thcknob s. need be turned but a `slight extent. The knob s is then pulledout to engage the pinion t with the gear u, and this knob is then slowlyturned until the anvil is just brought into engagement with the end ofthe plunger, this engagement being indicated by the free end o" the pinstarting to iall.

During these adjustments, it is, of course, understood that the forwardend 'of the swinging support h is held in raised position by the tensionof the spring 22. Upon completion of these adjustments, the piece to betested is positioned upon the work support. lVhere the piece is a screw,it is placed between the centers lO and 11 and the point n is gentlybrought into engage-- ment with one of the grooves of the piece to betested (see Fig. l) by rocking the arm /zy by means of the operatinghandle 63. The center 10 is then adjusted by means of the hand wheel 12so that the free end of the finger 0 will standl at the zero mark on thescale 51. This adjustment of the piece is possible owing to the factthat the center 1l is spring pressed. This spring pressed plunger isalso of advantage in that pin being trictionally held, these studs insuch it will hold the piece securely and steady between the centers. Theindicator is now raised and moved slightly to the right; a gauge blockcorresponding to the lead of the thread to be tested is positionedagainst the end of the plunger 54; and the indicator is then moved bythe knob Q until the scale i7 indicates t-hat the anvil is approximatelyin engagement with the gauge block. Then the indicator is slowly movedby turning the linob s until the anvil is in engagement with the gaugeblock. This engagement is indicated by the falling movement of the droppin (S-l, it being obvious that when the anvil is brought intoengagement with the gauge block, the plunger 54 will be moved veryslightly to the left, referring to Figs. l and 5, carrying with it thecollar 56 and the stud 62 fixed to the collar. Then the stud G2 is thusmoved, the distance between the stud. and the fixed stud 63 isincreased, which means that the friction on the pin Gel becomes less sothat the outer end of the pin may swing downwardly. The point 'a is thenengaged in one of the successive eonvolut-ions of the screw thread, and,if

the lead of this thread is not absolutely correct, the free end of thepointer finger o will stand to one or the other side of the Zero mark otthe scale 51. Owing to the fact that a slight movement ot the pin ismagnified many times in the finger 0, the extent of inaccuracies in thelead may be determined with the utmost precision. The successiveconvolutions ot the thread may be tested by successively interposing theproper size gauge blocks between the anvil and the drop pin arrangement.

It is to be noted that the swinging arm which carries the indicator ispivoted by means of knife edges, this being of advantage in that wearbetween the parts is practically eliminated, and lost motion between theparts is substantially obviated, thus assuring that no inaccuraciesoccur during the testing operation.

lhen the length, width or other dimension of a part or piece is to bemeasured, it may be placed on a suitable support (such as the support orblock o shown in Figs. 8 and 9) positioned on the base a in place of thestoel-:s c and d. Tn Figs. 8 and 9, the block o is illustrated as havinga surface supporting the work, and a vertical 'face or abutment 7l. Thesurface 7 O may be grooved as shown. To test the diameter of thecylinder T, the block c is so placed on the base that when the point nengages the face 71, the anvil 53 is just in engagement with the droppin plunger, and the finger o stands at Zero. The cylinder T is thenplaced on the surface 70; a gauge block corresponding to the desireddiameter of the cylinder is placed between the anvil and the drop pinplunger, and the indicator is then lowered into engagement with thecylinder. Tf the diameter of the cylinder is incorrect, the finger 0will indicate the extent of incorrectness. The device may also be usedto test the straightness or trueness of surfaces. For

example, by moving the indicator while the point 0 is in contact withthe face 7l (or the end face of the cylinder T), the trueness of thefaces may be determined by observing the extent, if any, of movement etthe finger o across the scale.

The embodiment oi my invention shown in Figs. G and 7 is very similar tothat ot' the preceeding figures. Tn this embodiment, instead of mountingthe drop pin arrangement p on the swinging arm and adjustably mountingthe indicating device m on that arm, the drop pin arrangement p ismounted (preferably for adjustment) on the base a, and the :tulcrum restis adjusted relatively to the drop pin arrangement. This latterconstruction is of advantage when it is desired to measure pieces ofwork of relatively greater length.

Referring to Figs. 6 and 7 more specifically, it will be seen that thedrop pin arrangement j) is carried by a stock which may be adjusted onthe way e. The fulerum member f has an anvil 53 adapted to cooperatewith the plunger 54:. This fulcrum member is adjusted or moved in thesame manner and for the same purpose as was th-e indicating device onthe arm h of the embodiment shown in Figs. l to 5. This is to say, thefulcrum member is moved by the screw r which is rotated by the knobs sand g. The stock 75 has a surface 76 tor supporting gauge blockspositioned between the plunger 54 and the anvil 53.

T claim as my invention:

1. Tn an apparatus of the character described, an indicator including apoint and an indicating finger associated therewith; a `drop pinarrangement having a definite position relative to said apparatus forindicating the proper positioning of said indicator and means foradjusting said indicator relative to said drop pin arrangement.

2. In an apparatus of the character described, an indicator having apoint and an indicating finger associated therewith, means forsupporting a piece to be tested, a drop pin arrangement having apredetermined position relative to said supporting means, said indicatorbeing movable in one direction relative to said supporting means tobring the point into and out of engagement with the piece to be tested,and means for adjusting said indicator at right angles to said firstdirection and relativ-e to said drop pin arrangement, said drop pinarrangement being adapted to indicate the proper positioning of saidindicator.

3. Tn an apparatus of the character described, an indicator including apoint adapted to engage the piece to be tested and an indicating lingerassociated therewith; a ldrop pin arrangement having a definite positionrelative to said apparatus for designating when said indicator' has beenbrought to proper position, means for adjusting said indicator relativeto said drop pin arrangement and a plurality ot interchangeable meansadapted to `be interposed between said indicator and drop pinarrangement for determining the extent ot adjustment oi said indicator.

4l. In an apparatus of the character described, an indicator having amounting and including` a point adapted to engage the piece to betested, an indicating nger and a. connection between said point andindicating :linger whereby a relativeljT small movement of the formerresults in a relatively large movement of the latter; a drop pinarrangement having a Idefinite position relative to said apparatus andhaving a spring pressed member, mea-ns r'or adjusting said indicatorrelative to said spring pressed member, and a plurality oit gauge blocksadapted to be interchangeably positioned between said indicator andmember.

5. ln an apparatus of the character described, an indicator including apoint :adapted to engage the piece to be tested, an indicating fingerand a connection between said point and indicating finger whereby arelatively small movement of the former results in a relatively largemovement et the latter, an adjustable mounting carrying said indicatorfor movement towards and away from the work, a drop pin arrangementhaving a definite position relative to said apparatus, means toradjusting said indicator relative to said drop pin arrangement and arest adapted to interchangeably support a piurality oi' gauge bloelrsbetween said mounting and said drop pin arrangement for determining theextent ot' adjustment ot' said indicator.

` (3. ln an apparatus of the character derm'ibed, a support adapted tobe moved into and out ot operative relation with respect to lthe pieceto be tested; an indicator1 adjustably mounted on said support andvincluding a point and an indicating linger associated therewith; a droppin arrangement having a definite position relative to said apparatus,said arrangement being carried by said support and including a memlierrelative to which said indicator is adapted to be moved; means lorarljusting said indicator relative to said drop pin ar angeinent and arest on said support on which are adapted to be interchangeablypositioned a plurz'ility ot gauge blocks letween said member and saidindicator. f

7. In an apparatus of the character described, a support adapted to bemoved towards and away trom the piece to be tested,

a slide mounted on said support for adjustment in parallelism with theaxis ot the piece to be tested; an indicator carried by said slide andincluding a pivoted point and an indicating linger associated therewith;a drop pin arrangement lixed to said support and including a springpressed plunger, an anvil on said indicator; a surface on said supportadapted to receive interchangeable gauge blocks interposed between saidplunger and anvil, and means for adjusting said slide relative to saiddrop pin arrangement.

8. ln an apparatus ot the character described, an adjustableV mounting,an indicator carried by said mounting and including a point and anindicating linger associated therewith, a screw associated with saidmounting for adjusting the same, means 'l'or rotating said screw at arelatively tast rate 'Ot speed to roughly adjust said indicator, andmeans associated with said screw for slowly rotating the same to cfiecta line adjustmentot said indicator. j 9. In an apparatus of thecharacter described, an adjustable mounting, an indicator carried bysaid mounting and including a point and an indica-ting linger associatedtherewith, a screw associated with said mounting tor adjusting the same,means for rotating said screw at a relatively fast rate ot speed toroughly adjust said indicator, means associated with said screw forslowly rotating the same to eiect a vline adjustment of said indicator,and a scale associtated with said screw tor indicating the ei;- tent ofadjustment of said indicator.

l0. ln an apparatus ot the character described, a support, a slidethereon, an indicator carried by said slide and including a point and anindicating linger associated therewith; a drop pin arrangement carriedby said support for indicating the proper positioning of said indicator;a screw associated with said slide for moving the same, means forrotating said screw at a relatively fast speed to roughly adjust saidindicator, and means associated with said screw 'lor slowly rotating thesame to eliect a line adjustment ot said indicator relative to said droppin arrangement.

ll. In an apparatus ot the character described, atulcrum member,swinging support fulcrumed thereon against other than swinging movement,an indicator including a member on said support, a point and a lingerassociated therewith, and means tor adjusting one oi said members inparallelism with the axis on which said support is tulcrumed.

l2. In an apparatus ot the character 1cscribed, a 'ulcrun'i member, aswinging support fulcrumed thereon against other than swinging'movement, an indicator including a member carried by said support, a

point adapted to engage the piece to be tested, and indicating fingerand a connection between said point and indicating linger whereby arelatively small movement of the point is indicated by a relativelylarge movement of the linger, means for adjusting one of said members inparallelism with the axis about which said support swings, and means forindicating the extent of such adjustment.

13. In an apparatus of the character described, a fulcrum rest, aswinging support fulerumed thereon against other than swinging movement,a slide mounted on said support for movement in parallelism with theaxis on which said support is fulcrumed; an indicator carried by saidslide and including a point adapted to engage the piece to be tested, anindicating finger, and a connection between said point and fingerwhereby a relatively small movement of the point is indicated by arelatively large movement of the finger; andv means carried by saidswinging support for designating when said indicator has been broughtinto predetermined position.

14. In an apparatus of the character described, a base, means thereonfor holding a. piece to be test-ed, a fulcrum member adjustably mountedon said base, a swinging support, knife edges for fulcruming saidsupport on said member, an indicator including a member on said support,a point, and an indicating linger associated therewith, means foradjusting one of saidmembers, and means for determining the extent ofsuch adjustment.

15. In an apparatus of the character described, a base, means thereonfor holding a piece to be tested, a fulcrum rest mounted for adjustmenton said base, a swinging support, knife edges for fulcruming saidsupport on said rest, an indicator adjustably mounted on the forward endof said support and including a pointand an indicating finger associatedtherewith; and means for normally holding the said swinging member withsaid indicator in raised'position.

16. In an apparatus of the character described, a pair of stocks eachhaving a center between which the piece to be tested is adapted to besupported, one of said centers being normally urged longitudinallytowards the other, and the other being longitudinally adjustable; anindica-tor including a point and an indicating finger associatedtherewith; and a support for said indicator so arranged that saidindicator may be moved towards and from the piece, and adjustedlongitudinally of said piece.

17. In an apparatus of the character described, a base; a pair of stocksthereon, each having a center between which the piece to be tested isadapted to be held, one of said centers being spring pressed towards theother one, and the other one being longitudinally adjustable; a swingingsupport fulcrumed on an axis parallel to said centers; an indicatorslidably mounted on said support in parallelism of the axis about whichsaid support is fulcrumed, and includ-- ing a point and an indicatingfinger associated therewith; and means for adjusting said indicator onsaid support.

18. An indicator of the character described, including a pivoted pointlever, a magnifying lever disposed in a vertical plane, a finger securedto said magnifying lever, a link lever supporting on one of its endssaid point lever and supporting on the other of its ends said magnifyinglever, and a spring for holding said levers in operative position.

19. An indicator of the character described, including a pivoted pointlever, a magnifying lever, a finger secured to said magnifying lever, alink lever supporting on one of its ends said point lever, andsupporting on the other of its ends said magnifying lever, and a springfor holding said levers in operative position.

20. An indicator of the character described, including a point lever, amagnifying lever, knife edge fulerums on which said levers arefulcrumed, a link lever, knife edge fulcrums between said link lever andsaid point lever and magnifying lever, and resilient means forsupporting all said levers.

21. An indicator of the character described, including a point lever, apoint carried thereby, a fixed fulcrum rest, a knife edge on said leverengaging the underside of said rest, a magnifying lever, a second fixedrest, a knife edge on said magnifying lever engaging the underside ofsaid second rest, a link lever having a rest at each end, an invertedVknife edge adjacent the upper end of said point lever engaging one ofsaid rests of said link lever, an inverted knife edge on said magnifyinglever immediately adja cent and spaced above said second rest andresting on the rest on the other end of said link lever, and a springfor holding the parts together.

22. In an apparatus of the character described, a fulcrum rest, aswinging support fulcrumed thereon, an indicating mechanism on saidsupport, and anti-friction means for supporting said support on saidrest against other than swinging movement.

23. In an apparatus of the character described, a fulcrum rest, asupport, knife edges for fulcruming said support on said rest, thrustmembers having a point engagement with said knife edges in alinementwith the edges to hold said support against other than swingingmovement, and an indicator on said swinging support.

BENGT M. w. Hanson.

